Thanks solstice for all the help. I am very good at tuning and reading plugs, Learned the hard way with all the bad engines I always seem to aquire, but oil choice has always been by manufactures advice. Never new that people were haveing engine failures due to the brands of oil they used. I always assumed it was due to engines being run to lean or run to hard with the wrong props and wrong oil ratios. Know that I see the concern I will spend more time researching.